Medical rubber articles and methods of manufacturing the same

Abstract

To provide a manufacturing method of a medical rubber article with reduced surface friction coefficient and adhesiveness.SOLUTION: A manufacturing method of a medical rubber article includes: a step of causing a vinyl compound expressed by a general formula (1) to have contact with a cured product of a medical rubber composition including halogenation butyl rubber as a base material polymer (a); and a step of irradiating, with ultraviolet light, the cured product after having contact with the vinyl compound. R-CH=CH2 (1) [In the formula, R denotes an alkyl group having 6 or more carbon atoms].SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a medical rubber article and a method for manufacturing the same, and more particularly to a technique for reducing the coefficient of friction and adhesion of the surface of a medical rubber article. [Background technology]

[0002] Medical rubber products use halogenated butyl rubber, which has excellent gas barrier properties. Because halogenated butyl rubber has only a small amount of double bonds that can be vulcanized, the surface of the vulcanized rubber product is sticky (high tack value). This results in poor sliding properties, and the rubber products tend to stick together when stored for long periods of time. To improve sliding properties and reduce frictional resistance, silicone oil is applied to the surface of the vulcanized rubber product, or it is laminated with a fluororesin film.

[0003] On the other hand, there is a surface modification method in which a polymer material is irradiated with ultraviolet light in order to improve the properties of the surface of the polymer material.

[0004] For example, Patent Document 1 discloses a method for modifying the surface of a material, in which a material made of a polymer having a -CH2- bond in a side chain or main chain is irradiated with ultraviolet light having a wavelength of 160 to 310 nm in an inert atmosphere, and then the material is irradiated with ultraviolet light having a wavelength of 200 nm or less in an oxidizing atmosphere, thereby making the wettability of the material surface uniform.

[0005] Patent Document 2 discloses a surface treatment method for a polymer material substrate (excluding fabric substrates), which imparts water repellency to the surface of the polymer material substrate by contacting the surface of the polymer material substrate with a vinyl compound represented by general formula (1) R-CH=CH2 (wherein R represents an alkyl group having 6 or more carbon atoms) and irradiating the surface with ultraviolet light. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 03-128941 [Patent Document 2] Japanese Patent Publication No. 2023-053773 Summary of the Invention [Problem to be solved by the invention]

[0007] To improve sliding properties, medical rubber articles are coated with silicone oil or laminated with a fluororesin film. However, when silicone oil-coated medical rubber articles come into contact with biopharmaceuticals, there is a risk of protein aggregation due to silicone particles. Therefore, medical rubber articles coated with silicone oil cannot be used for medical supplies that use biopharmaceuticals. In particular, there is a growing demand for silicone oil-free (SOF) plunger stoppers for prefilled syringes.

[0008] Furthermore, laminated medical rubber articles laminated with fluororesin films such as polytetrafluoroethylene (PTFE) films tend to have poor sealing properties when used as plunger stoppers for prefilled syringes because the elastic modulus of the PTFE film is 100 times higher than that of rubber.

[0009] To comply with the SOF regulations, a method is needed to reduce the coefficient of friction and adhesion of surfaces of medical rubber articles without using silicone oil.

[0010] The present invention has been made in view of the above circumstances, and aims to provide a novel medical rubber article having a reduced surface friction coefficient and reduced tackiness, and a method for producing the same. [Means for solving the problem]

[0011] The method for producing a medical rubber article of the present invention includes the steps of: (a) contacting a cured product of a medical rubber composition containing a halogenated butyl rubber as a base polymer with a vinyl compound represented by the following general formula (1): The method is characterized by including a step of irradiating the cured product after contact with the vinyl compound with ultraviolet light. R-CH=CH2(1) [In the formula, R represents an alkyl group having 6 or more carbon atoms.]

[0012] The medical rubber article of the present invention is characterized in that (a) one end of an alkyl chain having 8 or more carbon atoms is chemically bonded to the surface of a cured product of a medical rubber composition containing a halogenated butyl rubber as a base polymer.

[0013] The present inventors discovered that (a) by contacting a cured medical rubber composition containing halogenated butyl rubber as a base polymer with a specific vinyl compound and then irradiating it with ultraviolet light, the surface of the cured product is significantly modified to have a low coefficient of friction and low adhesion (a tack value of almost zero), and thus completed the present invention. [Effects of the Invention]

[0014] The present invention provides medical rubber articles with reduced surface coefficient of friction and tackiness. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is an explanatory view of one embodiment (plunger stopper) of the medical rubber article of the present invention. [Figure 2] FIG. 1 is an explanatory view of one embodiment (plunger stopper) of the medical rubber article of the present invention. [Figure 3] FIG. 1 is an explanatory view of one embodiment (rubber stopper) of the medical rubber article of the present invention. [Figure 4] FIG. 1 is an explanatory view of one embodiment (rubber stopper) of the medical rubber article of the present invention. [Figure 5] FIG. 1 is an explanatory view of one embodiment of the medical rubber article of the present invention (rubber stopper for vacuum blood collection tube). [Figure 6] FIG. 1 is an explanatory view of one embodiment of the medical rubber article of the present invention (rubber stopper for vacuum blood collection tube). [Figure 7] FIG. 1 is an explanatory view of one embodiment (nozzle cap) of the medical rubber article of the present invention. [Figure 8]FIG. 2 is an explanatory diagram of a method for measuring the coefficient of friction of a medical rubber article. DETAILED DESCRIPTION OF THE INVENTION

[0016] The method for producing a medical rubber article of the present invention includes the steps of: (a) contacting a cured product of a medical rubber composition containing a halogenated butyl rubber as a base polymer with a vinyl compound represented by the following general formula (1): The method is characterized by including a step of irradiating the cured product after contact with the vinyl compound with ultraviolet light. R-CH=CH2(1) [In the formula, R represents an alkyl group having 6 or more carbon atoms.]

[0017] The cured product of the medical rubber composition used in the manufacturing method of the present invention can be obtained by vulcanizing a medical rubber composition containing a halogenated butyl rubber as (a) the base polymer. First, the medical rubber composition used in the present invention will be described.

[0018] <Medical rubber composition> [(a) Base polymer] (a) The base polymer contains halogenated butyl rubber, which has excellent gas barrier properties and elution characteristics.

[0019] (a) Examples of halogenated butyl rubbers contained in the base polymer include chlorinated butyl rubber, brominated butyl rubber, and brominated copolymers of isobutylene and p-methylstyrene. These halogenated butyl rubbers may be used alone or in combination of two or more. The halogenated butyl rubber is preferably chlorinated butyl rubber or brominated butyl rubber. The chlorinated butyl rubber or brominated butyl rubber is, for example, obtained by adding or substituting chlorine or bromine to the isoprene structure of butyl rubber, specifically to the double bond and / or the carbon atom adjacent to the double bond. Note that butyl rubber is a copolymer obtained by polymerizing isobutylene and a small amount of isoprene. Note that the halogenated butyl rubber is preferably solid at room temperature (23°C).

[0020] The halogen content in the halogenated butyl rubber is preferably 0.5% by mass or more, preferably 1% by mass or more, more preferably 1.2% by mass or more, and is preferably 5% by mass or less, more preferably 4% by mass or less, and even more preferably 3% by mass or less.

[0021] (a) When the base polymer contains a chlorinated butyl rubber or a brominated butyl rubber as the halogenated butyl rubber, a crosslinking reaction occurs in the chlorinated or brominated isoprene moieties during the ultraviolet irradiation step. (a) When the base polymer contains brominated isobutylene-paramethylstyrene copolymer rubber (BIMS) as the halogenated butyl rubber, a crosslinking reaction occurs at the brominated paramethylstyrene sites during the ultraviolet irradiation step.

[0022] Specific examples of the chlorinated butyl rubber include Exxon (registered trademark) Chlorobutyl 1066 (halogen content: 1.25 wt %, Mooney viscosity: 38 ml) manufactured by Exxon Mobil Corporation. 1+8 (125°C, specific gravity: 0.92), Exxon Chlorobutyl 5066 (halogen content: 1.50 wt%, Mooney viscosity: 40 ml) 1+8 (125°C, specific gravity: 0.92); LANXESS X_BUTYL (registered trademark) CB1240 manufactured by LANXESS.

[0023] Specific examples of the brominated butyl rubber include Exxon Bromobutyl 2211 (halogen content: 2.0 wt %, Mooney viscosity: 32 ML) manufactured by Exxon Mobil Corporation. 1+8 (125°C, specific gravity: 0.93), Exxon Bromobutyl 2222 (halogen content: 2.0 wt%, Mooney viscosity: 32 ml) 1+8 (125°C, specific gravity: 0.93), Exxon Bromobutyl 2235 (halogen content: 2.1 wt%, Mooney viscosity: 39 ml) 1+8(125°C, specific gravity: 0.93), Exxon Bromobutyl 2244 (halogen content: 2.0 wt%, Mooney viscosity: 46 ml) 1+8 (125℃), Specific gravity: 0.93〕, Exxon Bromobutyl 2255〔Halogen content: 2.1wt%, Mooney viscosity: 46ML 1+8 (125°C, specific gravity: 0.93), Exxon Bromobutyl 6222 (halogen content: 2.4 wt%, Mooney viscosity: 32 ml) 1+8 (125°C, specific gravity: 0.93), Exxon Bromobutyl 7211 (halogen content: 2.0 wt%, Mooney viscosity: 32 ml) 1+8 (125℃), Specific gravity: 0.93〕, Exxon Bromobutyl 7244〔Halogen content: 2.1wt%, Mooney viscosity: 46ML 1+8 (125°C, specific gravity: 0.93); LANXESS X_BUTYL BBX2 manufactured by LANXESS.

[0024] (a) The base polymer may contain a rubber component other than halogenated butyl rubber. Examples of other rubber components include butyl rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, natural rubber, chloroprene rubber, nitrile rubber such as acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, norbornene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, acrylic rubber, ethylene-acrylate rubber, fluororubber, chlorosulfonated polyethylene rubber, epichlorohydrin rubber, silicone rubber, urethane rubber, polysulfide rubber, phosphane rubber, and 1,2-polybutadiene. These may be used alone or in combination of two or more.

[0025] When other rubber components are used, the content of the halogenated butyl rubber in the (a) base polymer is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 98% by mass or more. In a preferred embodiment, the (a) base polymer consists solely of the halogenated butyl rubber.

[0026] The medical rubber composition preferably contains a (b) crosslinking agent. The (b) crosslinking agent is blended to crosslink the halogenated butyl rubber component contained in the (a) base polymer. The (b) crosslinking agent is not particularly limited as long as it is capable of crosslinking the halogenated butyl rubber. Examples of the (b) crosslinking agent include sulfur, metal oxides, resin crosslinking agents, organic peroxides, and triazine derivatives, which may be used alone or in combination of two or more.

[0027] Examples of sulfur used as a crosslinking agent include insoluble sulfur, powdered sulfur, finely divided sulfur, precipitated sulfur, colloidal sulfur, and sulfur chloride.

[0028] Examples of metal oxides used as crosslinking agents include magnesium oxide, calcium oxide, zinc oxide, and copper oxide.

[0029] Examples of the resin crosslinking agent include alkylphenol formaldehyde resins such as alkylphenol formaldehyde resin, heat-reactive phenol resin, phenol dialcohol resin, bisphenol resin, and heat-reactive bromomethyl alkylated phenol resin.

[0030] Specific examples of the organic peroxides include dialkyl peroxides, peroxyesters, peroxyketals, and hydroperoxides. Examples of dialkyl peroxides include di(2-t-butylperoxyisopropyl)benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylcumyl peroxy, di-t-hexyl peroxy, di-t-butyl peroxy, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3. Examples of peroxyesters include t-butyl peroxymaleate, t-butylperoxy-3,3,5-trimethylcyclohexanoate, t-butyl peroxylaurate, t-butylperoxyisopropyl monocarbonate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butyl peroxyacetate, and t-butyl peroxybenzoate. Examples of peroxyketals include 1,1-di(t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-di(t-hexylperoxy)cyclohexane, 1,1-di(t-butylperoxy)-2-methylcyclohexane, 1,1-di(t-butylperoxy)cyclohexane, 2,2-di(t-butylperoxy)butane, n-butyl-4,4-di(t-butylperoxy)valerate, and 2,2-di(4,4-di(t-butylperoxy)cyclohexyl)propane. Examples of hydroperoxides include p-menthane hydroperoxide and diisopropylbenzene hydroperoxide. These organic peroxides may be used alone or in combination of two or more.

[0031] The triazine derivative used as the crosslinking agent includes, for example, a compound represented by the general formula (1).

[0032] [ka]

[0033] [Wherein R is -SH, -OR 1 , -SR 2 , -NHR 3 or -NR 4 R 5 (R 1 , R 2 , R 3 , R 4 and R 5 represents an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkylaryl group, or a cycloalkyl group. 4 and R 5 may be the same or different. 1 and M 2 is H, Na, Li, K, 1 / 2Mg, 1 / 2Ba, 1 / 2Ca, an aliphatic primary amine, a secondary amine, or a tertiary amine, a quaternary ammonium salt, or a phosphonium salt. 1 and M 2 may be the same or different.]

[0034] In general formula (1), examples of the alkyl group include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, n-hexyl, 1,1-dimethylpropyl, octyl, isooctyl, 2-ethylhexyl, decyl, and dodecyl. Examples of the alkenyl group include alkenyl groups having 1 to 12 carbon atoms, such as vinyl, allyl, 1-propenyl, isopropenyl, 2-butenyl, 1,3-butadienyl, and 2-pentenyl. Examples of the aryl group include monocyclic or fused polycyclic aromatic hydrocarbon groups, such as aryl groups having 6 to 14 carbon atoms, such as phenyl, naphthyl, anthryl, phenanthryl, and acenaphthylenyl. Examples of aralkyl groups include aralkyl groups having 7 to 19 carbon atoms, such as benzyl, phenethyl, diphenylmethyl, 1-naphthylmethyl, 2-naphthylmethyl, 2,2-diphenylethyl, 3-phenylpropyl, 4-phenylbutyl, 5-phenylpentyl, 2-biphenylylmethyl, 3-biphenylylmethyl, and 4-biphenylylmethyl. Examples of alkylaryl groups include alkylaryl groups having 7 to 19 carbon atoms, such as tolyl, xyl, and octylphenyl. Examples of cycloalkyl groups include cycloalkyl groups having 3 to 9 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and cyclononyl.

[0035] Specific examples of the triazine derivative represented by general formula (1) include 2,4,6-trimercapto-s-triazine, 2-methylamino-4,6-dimercapto-s-triazine, 2-(n-butylamino)-4,6-dimercapto-s-triazine, 2-octylamino-4,6-dimercapto-s-triazine, 2-propylamino-4,6-dimercapto-s-triazine, 2-diallylamino-4,6-dimercapto-s-triazine, 2-dimethylamino-4,6-dimercapto-s-triazine, 2-dibutylamino- Examples include 4,6-dimercapto-s-triazine, 2-di(iso-butylamino)-4,6-dimercapto-s-triazine, 2-dipropylamino-4,6-dimercapto-s-triazine, 2-di(2-ethylhexyl)amino-4,6-dimercapto-s-triazine, 2-dioleylamino-4,6-dimercapto-s-triazine, 2-laurylamino-4,6-dimercapto-s-triazine, and 2-anilino-4,6-dimercapto-s-triazine, or sodium salts or disodium salts thereof.

[0036] Among these, 2,4,6-trimercapto-s-triazine, 2-dialkylamino-4,6-dimercapto-s-triazine, and 2-anilino-4,6-dimercapto-s-triazine are preferred, and 2-dibutylamino-4,6-dimercapto-s-triazine is particularly preferred due to its easy availability.

[0037] Examples of triazine derivatives include one or more of 6-[bis(2-ethylhexyl)amino]-1,3,5-triazine-2,4-dithiol, 6-diisobutylamino-1,3,5-triazine-2,4-dithiol, 6-dibutylamino-1,3,5-triazine-2,4-dithiol, 6-dibutylamino-1,3,5-triazine-2,4-dithiol monosodium, 6-anilino-1,3,5-triazine-2,4-dithiol, and 1,3,5-triazine-2,4,6-trithiol.

[0038] In the medical rubber composition used in the present invention, one type of triazine derivative may be used alone, or two or more types may be used in combination.

[0039] Since the chlorinated butyl rubber and the brominated butyl rubber have different crosslinking mechanisms, it is preferable to select and use the crosslinking component that is most suitable for crosslinking. When the medical rubber composition contains a chlorinated butyl rubber as the halogenated butyl rubber, it is preferable to contain a triazine derivative as the crosslinking agent (b). Furthermore, when the medical rubber composition contains a brominated butyl rubber as the halogenated butyl rubber, it is preferable to contain a metal oxide as the crosslinking agent (b).

[0040] The content of (b) the crosslinking agent in the medical rubber composition is preferably 0.2 parts by mass or more, more preferably 0.4 parts by mass or more, and even more preferably 0.6 parts by mass or more, and is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the (a) base polymer component. This is because, when the content of (b) the crosslinking agent is within the above range, a rubber having good rubber properties (hardness, tensile strength, Cset) and good processability (less discoloration) can be obtained.

[0041] When a chlorinated butyl rubber is used as the halogenated butyl rubber and a triazine derivative is used as the (b) crosslinking agent, the content of the (b) crosslinking agent in the medical rubber composition is preferably 0.2 parts by mass or more, more preferably 0.4 parts by mass or more, and even more preferably 0.6 parts by mass or more, and preferably 4 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less, per 100 parts by mass of the (a) base polymer component. This is because, when the content of the (b) crosslinking agent is within the above range, a rubber with good rubber properties (hardness, tensile strength, Cset) and good processability (less discoloration) can be obtained.

[0042] When a brominated butyl rubber is used as the halogenated butyl rubber and a metal oxide is used as the (b) crosslinking agent, the content of the (b) crosslinking agent in the medical rubber composition is preferably 1 part by mass or more, more preferably 1.5 parts by mass or more, and even more preferably 2 parts by mass or more, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the (a) base polymer component. This is because, when the content of the (b) crosslinking agent is within the above range, a rubber with good rubber properties (hardness, tensile strength, Cset) and good processability (less discoloration) can be obtained.

[0043] The medical rubber composition preferably does not contain a vulcanization accelerator, as this may result in the vulcanization accelerator remaining in the final rubber product and leaching into the medicinal solution in a syringe, etc. Examples of the vulcanization accelerator include guanidine-based accelerators (e.g., diphenyl guanidine), thiuram-based accelerators (e.g., tetramethylthiuram disulfide, tetramethylthiuram monosulfide), dithiocarbamate-based accelerators (e.g., zinc dimethyldithiocarbamate), thiazole-based accelerators (e.g., 2-mercaptobenzothiazole, dibenzothiazyl disulfide), and sulfenamide-based accelerators (N-cyclohexyl-2-benzothiazole sulfenamide, Nt-butyl-2-benzothiazole sulfenamide).

[0044] The medical rubber composition may further contain an acid acceptor. The acid acceptor functions to absorb chlorine-based gases and bromine-based gases generated during crosslinking of the halogenated butyl rubber and to prevent the occurrence of crosslinking inhibition due to these gases. The acid acceptor also functions as a scorch inhibitor during crosslinking of the halogenated butyl rubber and to prevent the compression set of the medical rubber part from increasing.

[0045] Examples of the acid acceptor include hydrotalcite, metal oxides, and metal hydroxides.

[0046] Examples of hydrotalcite include Mg4.5 Al2(OH) 13 CO3·3.5H2O, Mg 4.5 Al2(OH) 13 CO3, Mg4Al2(OH) 12 CO3·3.5H2O, Mg6Al2(OH) 16 CO3·4H2O, Mg5Al2(OH) 14 CO3·4H2O, Mg3Al2(OH) 10 Examples of suitable acid acceptors include Mg-Al hydrotalcites such as CO3·1.7H2O. Examples of suitable metal oxides include magnesium oxide, calcium oxide, and zinc oxide. Examples of suitable metal hydroxides include calcium hydroxide. These acid acceptors may be used alone or in combination of two or more. The metal oxides used as crosslinking agents described above can also function as acid acceptors.

[0047] The content of the acid acceptor is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 15 parts by mass or less, and more preferably 10 parts by mass or less, relative to 100 parts by mass of the (a) base polymer component. This is because, when the content of the acid acceptor is within the above range, rust formation on a mold or the like can be suppressed and defects such as the raw material itself becoming white spots can be reduced.

[0048] The medical rubber composition may further contain a filler. Examples of the filler include inorganic fillers such as clay and talc. Among these, inorganic fillers are preferred, and clay or talc is more preferred. The filler functions to adjust the rubber hardness of the medical rubber part and also functions as an extender to reduce the production cost of the medical rubber part.

[0049] Examples of the clay include calcined clay and kaolin clay. Specific examples of the clay include SILLITIN® Z manufactured by HOFFMANN MINERAL, SATINTONE® W manufactured by ENGELHARD, NN kaolin clay manufactured by Tsuchiya Kaolin Kogyo Co., Ltd., and PoleStar 200R manufactured by Imerys Specialties Japan.

[0050] Specific examples of the talc include Hitron A manufactured by Takehara Chemical Industry Co., Ltd., MICRO ACE (registered trademark) K-1 manufactured by Nippon Talc Co., Ltd., and Mistron (registered trademark) Vapor manufactured by Imerys Specialties Japan.

[0051] The content of the filler in the medical rubber composition is preferably set appropriately depending on the rubber hardness, etc., of the intended medical rubber article. The content of the filler in the medical rubber composition is, for example, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 20 parts by mass or more, and preferably 200 parts by mass or less, more preferably 150 parts by mass or less, and even more preferably 100 parts by mass or less, per 100 parts by mass of the (a) base polymer component.

[0052] The medical rubber composition may further contain colorants such as titanium oxide and carbon black, lubricants such as stearic acid, processing aids, polyethylene glycol as a crosslinking activator, process oil, etc. in appropriate proportions.

[0053] The medical rubber composition is obtained by kneading (a) a base polymer, (b) a crosslinking agent, and other compounding materials added as needed. Kneading can be carried out using, for example, an open roll or an internal kneader. The kneaded product is preferably formed into a ribbon, sheet, pellet, or the like, and more preferably formed into a sheet.

[0054] The method for producing a medical rubber article of the present invention may include a step of curing the medical rubber composition. The cured product of the medical rubber composition used in the present invention is obtained by vulcanizing (crosslinking) the medical rubber composition. A cured product of the medical rubber composition having a desired shape can be obtained by press-molding a kneaded product in the form of a ribbon, sheet, or pellet. The crosslinking reaction of the medical rubber composition progresses during pressing. The molding temperature is, for example, preferably 130°C or higher, more preferably 140°C or higher, and preferably 200°C or lower, more preferably 190°C or lower. The molding time is preferably 2 minutes or longer, more preferably 3 minutes or longer, and preferably 60 minutes or shorter, more preferably 30 minutes or shorter. The molding pressure is preferably 0.1 MPa or higher, more preferably 0.2 MPa or higher, and preferably 10 MPa or lower, more preferably 8 MPa or lower.

[0055] The cured product of the medical rubber composition to which the present invention is applied may have at least a portion of its surface coated with an inactive resin layer. For example, by press-molding a sheet made of the medical rubber composition with an inactive resin film superimposed thereon, at least a portion of the surface of the cured product of the medical rubber composition is coated with the inactive resin layer.

[0056] The inactive resin layer may be applied to at least a portion of the surface of the medical rubber article, and is preferably applied appropriately depending on the shape of the medical rubber article. In particular, it is preferable to provide an inactive resin layer on the surface of the medical rubber article that comes into contact with chemicals. In this embodiment, the inactive resin layer exhibits good chemical resistance and improves the sliding properties of the surface not provided with the inactive resin layer.

[0057] The resin constituting the inactive resin layer is not particularly limited, but examples thereof include at least one fluororesin selected from the group consisting of tetrafluoroethylene-ethylene copolymer (ETFE), polytetrafluoroethylene (PTFE), and polychlorotetrafluoroethylene (PCTFE), or a non-fluororesin, in terms of obtaining good chemical resistance.

[0058] Tetrafluoroethylene-ethylene copolymer (ETFE) is a copolymer of ethylene and tetrafluoroethylene in a molar ratio of 30 / 70 to 70 / 30. Modified ETFE can also be obtained by copolymerizing other components for the purpose of modification. These other components include fluorine-containing olefins and hydrocarbon olefins. Specifically, these include α-olefins such as propylene and butene; fluorine-containing olefins such as hexafluoropropylene, vinylidene fluoride, perfluorobutylethylene, and trifluorochloroethylene; vinyl ethers such as ethylene vinyl ether, perfluoromethyl vinyl ether, and perfluoropropyl vinyl ether; and fluorine-containing acrylates. These components are copolymerized at approximately 2 to 10 mol% to modify ETFE.

[0059] As the modified ETFE, ETFE having a functional group that imparts adhesiveness can be suitably used, and examples of the functional group include a carboxyl group, a carboxyl anhydride group, an epoxy group, a hydroxyl group, an isocyanate group, an ester group, an amide group, an aldehyde group, an amino group, a cyano group, a carbon-carbon double bond, a sulfonic acid group, an ether group, etc. In addition, an example of a commercially available modified ETFE product is Fluon AH-2000 manufactured by Asahi Glass Co., Ltd.

[0060] Examples of non-fluorine resins include olefin-based resins. Examples of the olefin-based resins include polyethylene-based resins such as polyethylene, ethylene-propylene copolymer, ethylene-propylene-non-conjugated diene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-ethyl acrylate copolymer, and chlorinated polyethylene; polypropylene-based resins such as polypropylene, propylene-ethylene random copolymer, propylene-ethylene block copolymer, and chlorinated polypropylene; polybutene, polyisobutylene, polymethylpentene, and copolymers of cyclic olefins; and polyethylene (particularly ultra-high molecular weight polyethylene (UHMWPE)). The olefin-based resins may contain fluorine.

[0061] The thickness of the inactive resin film used may be adjusted appropriately according to the shape and size of the medical rubber article, but is preferably 10 μm or more, more preferably 20 μm or more, even more preferably 30 μm or more, and preferably 150 μm or less, more preferably 130 μm or less, and even more preferably 110 μm or less. If the thickness of the inactive resin film is within the above range, the film will not break during product molding, and wrinkles or floating defects will not occur on the film surface of the product after molding, and both moldability and product properties can be achieved.

[0062] The arithmetic mean roughness Ra of the inactive resin film ranges from 0.01 to 0.03 μm for cast films and extruded films to 0.10 μm for skived films, but by setting the surface roughness of the mold to 0.03 μm or less, medical rubber articles with excellent liquid adhesion and airtightness can be obtained. There is no particular lower limit for Ra of the inactive film itself.

[0063] The inactive resin film is preferably subjected to a treatment to enhance its adhesiveness to rubber, etc. Examples of treatments to enhance adhesiveness include chemical treatments, treatments to roughen the surface of the film, and combinations of these, and specific examples include sodium treatment, glow discharge treatment, plasma treatment (discharge treatment) under atmospheric pressure or in a vacuum, excimer laser treatment (discharge treatment), and ion beam treatment.

[0064] <Method of manufacturing medical rubber articles> The method for producing medical rubber articles of the present invention will now be described. The method for producing a medical rubber article of the present invention includes a step of contacting a cured product of the medical rubber composition with a vinyl compound represented by the following general formula (1) (hereinafter, this step may be referred to as the "vinyl compound contacting step"), and a step of irradiating the cured product after contact with the vinyl compound with ultraviolet light (hereinafter, this step may be referred to as the "ultraviolet light irradiation step"). R-CH=CH2(1) [In the formula, R represents an alkyl group having 6 or more carbon atoms.]

[0065] [Vinyl compound contact process] The vinyl compound contacting step is a step in which the cured medical rubber composition is contacted with the vinyl compound represented by the general formula (1). The vinyl compound represented by the general formula (1) attached to the surface of the cured product in the vinyl compound contacting step undergoes UV irradiation, which cleaves the double bond of the vinyl compound to generate alkyl radicals, which then bond to the surface of the cured product. That is, one end (the end on the double bond side) of the alkyl chain (the portion represented by R) of the vinyl compound chemically bonds to the surface of the cured product. As a result, the surface free energy of the cured product is reduced, resulting in a low coefficient of friction and low adhesion on the surface of the cured product.

[0066] The vinyl compound used in the vinyl compound contacting step is an α-olefin in which R is an alkyl group having 6 or more carbon atoms. If the alkyl group represented by R has 6 or more carbon atoms, the effect of reducing the friction coefficient and adhesion of the cured product surface is more likely to be achieved. In order to further enhance the effect of reducing the friction coefficient and adhesion of the cured product surface, the number of carbon atoms in the alkyl group represented by R is preferably 8 or more, more preferably 10 or more, and even more preferably 12 or more. Furthermore, the number of carbon atoms in the alkyl group represented by R is not particularly limited, but is preferably 20 or less, more preferably 19 or less, and even more preferably 18 or less. This is because if the alkyl group represented by R has 20 or more carbon atoms, high sliding properties are lost.

[0067] The alkyl group represented by R may be linear, branched, or cyclic, but is preferably linear in order to further enhance the effect of reducing the friction coefficient and tackiness of the cured product surface.

[0068] Specific examples of the vinyl compound include 1-octadecene, 1-nonadecene, 1-eicosene, 1-heneicosene, and 1-docosene. The alkyl group of the vinyl compound may be linear, branched, or cyclic, but linear alkyl group is preferred. These vinyl compounds may be used alone or in combination of two or more.

[0069] The method for contacting the vinyl compound with the cured medical rubber composition is not particularly limited, and examples thereof include applying a liquid vinyl compound or a vinyl compound-containing liquid to the surface of the cured medical rubber composition, immersing the cured medical rubber composition in a liquid vinyl compound or a vinyl compound-containing liquid, and placing the cured medical rubber composition in a container containing a gaseous vinyl compound. It is also preferable to mask a portion of the surface of the cured medical rubber composition so that the vinyl compound contacts only the desired area. Among these, applying a vinyl compound-containing liquid to the surface of the cured medical rubber composition is preferred from the viewpoint of uniform application. The application method is not particularly limited, and examples include known methods such as spraying or applying with a brush.

[0070] The vinyl compound-containing liquid is preferably a solution in which a vinyl compound is dissolved. The solvent for dissolving the vinyl compound is not particularly limited, and examples thereof include hexane, butyl acetate, benzene, and toluene.

[0071] In the vinyl compound-containing liquid, the concentration of the vinyl compound is not particularly limited, but is preferably 2.0 g / L or more, more preferably 5.0 g / L or more, even more preferably 8.0 g / L or more, and is preferably 25.0 g / L or less, more preferably 20.0 g / L or less, and even more preferably 15.0 g / L or less. This is because, when the concentration of the vinyl compound is within the above range, the effect of reducing the friction coefficient and adhesion by the vinyl compound is easily exhibited.

[0072] In the vinyl compound contact step, it is preferable to remove the solvent of the vinyl compound-containing liquid adhering to the surface of the cured product. The method for removing the solvent of the vinyl compound-containing liquid is not particularly limited, and can be performed by, for example, natural drying or vacuum drying.

[0073] The amount of the vinyl compound attached to the cured product of the medical rubber composition is not particularly limited, but is preferably 0.19 mg / cm 2It is preferable that the concentration is 0.47 mg / cm or more. 2 More preferably, it is 0.75 mg / cm or more. 2 More preferably, it is 2.34 mg / cm or more. 2 Preferably, it is 1.90 mg / cm or less. 2 More preferably, it is 1.41 mg / cm or less. 2 It is more preferable that the amount of the vinyl compound applied is within the above range, because the effect of reducing the coefficient of friction and tackiness due to the vinyl compound is easily exhibited.

[0074] <Ultraviolet irradiation process> The method for producing a medical rubber article of the present invention includes a step of irradiating the cured product after contact with the vinyl compound with ultraviolet light (ultraviolet light irradiation step). The cured product of the medical rubber composition irradiated with ultraviolet light may be molded into the shape of the final medical rubber article, or may be a preform before being molded into the shape of the final medical rubber article.

[0075] The method for irradiating the cured product of the medical rubber composition with ultraviolet light is not particularly limited, but for example, it may be possible to irradiate at least a portion of the surface of the cured product of the medical rubber composition with ultraviolet light using a light source that emits ultraviolet light. Examples include an embodiment in which ultraviolet light is irradiated only to the areas of the surface of the cured product of the medical rubber composition that are coated with the vinyl compound, or an embodiment in which ultraviolet light is irradiated to the entire cured product, including the areas that are coated with the vinyl compound. It is also preferable to mask a portion of the surface of the cured product of the medical rubber composition and irradiate ultraviolet light only to the desired areas.

[0076] The wavelength of the ultraviolet light is preferably 160 nm or more, more preferably 165 nm or more, and even more preferably 170 nm or more. This is because ultraviolet light with a wavelength of 160 nm or more can modify the surface. Furthermore, the upper limit of the ultraviolet light wavelength is not particularly limited, but is preferably 380 nm or less, more preferably 300 nm or less, and even more preferably 200 nm or less. When the wavelength of ultraviolet light is 380 nm or less, the energy of the ultraviolet light is high, which increases the crosslinking efficiency of the halogenated butyl rubber and reduces deformation. Furthermore, high-energy ultraviolet light decomposes and evaporates low-molecular-weight components that contribute to the surface tackiness of the cured product of the medical rubber composition, thereby achieving low tackiness. Furthermore, the evaporation of the low-molecular-weight components roughens the surface of the cured product, further reducing the coefficient of friction. Among these, vacuum ultraviolet light with a wavelength of 200 nm or less is particularly preferred, as it can more effectively achieve the effects of the present invention.

[0077] The light source for emitting the ultraviolet light is not particularly limited as long as it can emit ultraviolet light in the wavelength range. Examples include low-pressure mercury lamps, high-pressure mercury lamps, and excimer lamps. Excimer lamps are particularly preferred because they have high energy and can modify surfaces in a relatively short time. The excimer lamp emits ultraviolet light with different wavelengths depending on the type of discharge gas used. For example, xenon (Xe2) emits ultraviolet light with a center wavelength of 172 nm, xenon chloride (XeCl) emits ultraviolet light with a center wavelength of 308 nm, xenon bromide (XeBr) emits ultraviolet light with a center wavelength of 283 nm, xenon iodide (XeI) emits ultraviolet light with a center wavelength of 193 nm, argon fluoride (ArF) emits ultraviolet light with a center wavelength of 165 nm, krypton chloride (KrCl) emits ultraviolet light with a center wavelength of 207 nm, and krypton bromide (KrBr) emits ultraviolet light with a center wavelength of 172 nm, 308 nm, 283 nm, 253 nm, 193 nm, 165 nm, 222 nm, and 207 nm, respectively. In the present invention, an excimer lamp that emits vacuum ultraviolet light with a central wavelength of 200 nm or less is preferred, and an excimer lamp using xenon (central wavelength: 172 nm) is particularly preferred.

[0078] In the ultraviolet irradiation step, the cumulative irradiance of ultraviolet light on the cured product of the medical rubber composition is 1000 mJ / cm 2 It is preferable that the concentration is 3000 mJ / cm or more. 2 More preferably, it is 5000 mJ / cm or more. 2 It is more preferable that the cumulative irradiance of the cured product of the medical rubber composition is 1000 mJ / cm or more. 2 If the ultraviolet ray irradiance is above 50000 mJ / cm, the crosslinking of the halogenated butyl rubber is sufficiently performed and the low molecular weight components that contribute to the surface adhesion of the cured product of the medical rubber composition are more easily decomposed. 2 Preferably, it is 45,000 mJ / cm or less. 2 More preferably, it is 40,000 mJ / cm or less. 2 It is even more preferable that the cumulative irradiance on the cured product of the medical rubber composition is 50,000 mJ / cm2 or less. This is because a balance can be achieved between the life of the irradiation equipment and the efficiency of surface modification. The cumulative irradiance of ultraviolet light on the cured product of the medical rubber composition is the total irradiance (arrival irradiance) of ultraviolet light that reaches the surface of the cured product of the medical rubber composition, and can be calculated by multiplying the intensity (arrival intensity) of ultraviolet light that reaches the surface of the cured product of the medical rubber composition by the irradiation time of ultraviolet light.

[0079] The reaching intensity and irradiation time of the ultraviolet light may be adjusted appropriately so that the integrated illuminance falls within the range described above. Usually, the reaching intensity of the ultraviolet light is 10 mW / cm 2 / sec~100mW / cm 2 The irradiation time is preferably 10 to 5000 seconds, and the UV intensity is preferably 1 / sec. This is because by setting the UV intensity and irradiation time within these ranges, it is easy to achieve an integrated illuminance within the above range.

[0080] The distance between the surface of the cured medical rubber composition and the light source (lamp) that emits ultraviolet light is not particularly limited, but is preferably 1 mm to 20 mm in order to improve the uniformity of ultraviolet light irradiation.

[0081] In the present invention, by irradiating the cured product of the medical rubber composition after contact with the vinyl compound with ultraviolet light, the surface of the cured product can be significantly modified to have a low coefficient of friction and low tack.

[0082] In the manufacturing method of the present invention, when at least a portion of the surface of the cured product of the medical rubber composition is coated with an inactive resin layer, it is preferable to bring a vinyl compound into contact with at least a portion of the exposed surface of the cured product that is not coated with the inactive resin layer and irradiate it with ultraviolet light. As long as ultraviolet light is irradiated to the portion of the cured product surface where the vinyl compound is attached, ultraviolet light may be irradiated only to a portion of the exposed surface of the cured product, or ultraviolet light may be irradiated to the entire exposed surface of the cured product.

[0083] In the manufacturing method of the present invention, when at least a portion of the surface of the cured product of the medical rubber composition is coated with an inactive resin layer, it is preferable to bring the vinyl compound into contact with only the exposed surface of the cured product that is not coated with the inactive resin layer. When the vinyl compound is brought into contact with the inactive resin layer, it is preferable to remove the vinyl compound adhering to the inactive resin layer without irradiating the inactive resin layer with ultraviolet light.

[0084] The method for producing a medical rubber article of the present invention may include the steps of processing the cured product of the medical rubber composition into a predetermined shape, washing, sterilizing, and drying. For example, the medical rubber article is produced by cutting and removing unnecessary parts from the cured product of the medical rubber composition after ultraviolet irradiation to form the predetermined shape, and then washing, sterilizing, drying, and packaging the product. Note that cutting and removing unnecessary parts to form the predetermined shape may be performed before irradiating the cured product of the medical rubber composition with ultraviolet light.

[0085] The medical rubber article obtained by the manufacturing method of the present invention can achieve a low coefficient of friction and low tack without using silicone oil, and therefore can be suitably used as a medical rubber article that meets the SOF regulations and requires a low coefficient of friction and low tack.

[0086] In order to comply with SOF, it is preferable that the medical rubber article obtained by the manufacturing method of the present invention is not coated with silicone oil. Examples of the silicone oil include dimethylpolysiloxane, methylphenylpolysiloxane, and modified products thereof.

[0087] Examples of medical rubber articles obtainable by the manufacturing method of the present invention include rubber stoppers and sealing members for containers for various drugs such as liquid drugs, powder preparations, and freeze-dried preparations, rubber stoppers for vacuum blood collection tubes, plunger stoppers (gaskets) for pre-filled syringes, and sliding or sealing parts such as nozzle caps. Among these, medical rubber parts (e.g., rubber stoppers and plunger stoppers) that require a low coefficient of friction and low adhesion are preferred, and plunger stoppers that require excellent sliding properties are particularly preferred.

[0088] Of these, rubber stoppers and sealing members, including those for vials and infusion preparation containers, preferably have a rubber hardness of 35 or more and 60 or less in durometer type A hardness (Shore A hardness) measured in accordance with the measurement method described in Japanese Industrial Standard JIS K6253-3:2012 "Vulcanized rubber and thermoplastic rubber - Determination of hardness - Part 3: Durometer hardness."

[0089] Furthermore, the sliding or sealing parts of gaskets and nozzle caps for prefilled syringes preferably have a Shore A hardness of 40 or more and 70 or less.

[0090] The rubber hardness of medical rubber articles can be adjusted by changing the blending ratio of each raw material.

[0091] <Medical rubber parts> The present invention includes a medical rubber article characterized in that one end of an alkyl chain having 8 or more carbon atoms is chemically bonded to the surface of a cured product of a medical rubber composition containing halogenated butyl rubber as a base polymer.

[0092] By chemically bonding one end of an alkyl chain having 8 or more carbon atoms to the surface, the surface free energy of the medical rubber article is reduced, thereby achieving a low coefficient of friction and low adhesion. In order to further enhance the effect of reducing the coefficient of friction and adhesion of the surface of the medical rubber article, the number of carbon atoms in the alkyl chain is preferably 8 or more, more preferably 10 or more, and even more preferably 12 or more. Furthermore, the number of carbon atoms in the alkyl chain is not particularly limited, but is preferably 20 or less, more preferably 19 or less, and even more preferably 18 or less. This is because if the carbon atom number in the alkyl chain is 20 or less, high sliding properties can be achieved.

[0093] The alkyl chain may be linear, branched, or cyclic, but is preferably linear in order to further enhance the effect of reducing the coefficient of friction and adhesion of the surface of the medical rubber part.

[0094] Specific examples of the alkyl chain include octyl chain, nonyl chain, decyl chain, undecyl chain, dodecyl chain, tridecyl chain, tetradecyl chain, pentadecyl chain, hexadecyl chain, heptadecyl chain, octadecyl chain, nonadecyl chain, and eicosyl chain. The alkyl chain may be linear, branched, or cyclic, but is preferably linear. The alkyl chain chemically bonded to the surface of the cured product of the medical rubber composition may be of one type or two or more types.

[0095] The components of the medical rubber composition constituting the medical rubber article of the present invention and the conditions for molding the cured product are as described above.

[0096] Specific examples of medical rubber articles to which the present invention is applied will be described below. <Plunger stopper> Figure 1 is an exploded view of a medical syringe in which the medical rubber part of the present invention is used, a syringe known as a prefillable syringe 30. In Figure 1, half of the syringe barrel 31 and plunger stopper 33 are shown in cross section. The prefillable syringe 30 includes a cylindrical syringe barrel 31, a plunger 32 that is combined with the syringe barrel 31 and can move back and forth within the syringe barrel 31, and a plunger stopper 33 that is attached to the tip of the plunger 32.

[0097] The plunger 32 is formed, for example, from a resin plate piece having a cross-shaped cross section, and is provided at its tip with a head portion 38 to which the plunger stopper 33 is attached. The head portion 38 is made of resin and formed integrally with the plunger 32, and is machined into a male thread shape. The plunger stopper 33 is a roughly cylindrical short-axis member, and its tip surface has, for example, an obtuse-angled chevron shape with the center of the axis protruding. A female thread-shaped mating recess 35 is formed axially from the rear end surface. The head portion 38 of the plunger 32 is screwed into the mating recess 35 of the plunger stopper 33, thereby attaching the plunger stopper 33 to the tip of the plunger 32.

[0098] 2 is a half-sectional front view of an example of a plunger stopper. Plunger stopper 40 includes a main body 41 made of a cured medical rubber composition and an inactive resin layer 42 that covers part of the surface of the main body. Plunger stopper 40 has a liquid-contacting surface 47 that faces the medicinal solution and a sliding surface 46 that comes into contact with the syringe barrel.

[0099] 2, when plunger stopper 40 is inserted into the syringe barrel, only mountain-shaped liquid contact surface 47 that comes into contact with the drug solution is coated with inactive resin layer 42. As inactive resin layer 42, for example, a polytetrafluoroethylene film is preferable.

[0100] The sliding surface (outer peripheral surface) 46 where the plunger stopper 40 comes into contact with the syringe barrel is not provided with the inactive resin layer 42, and the cured medical rubber composition is exposed. A vinyl compound is applied to the surface of the cured sliding surface, and ultraviolet light is irradiated. The sliding surface (outer peripheral surface) 46 has high slidability.

[0101] The plunger stopper 40 has a short cylindrical shape and has a plurality of annular ribs 43, 44, and 45 on an outer peripheral surface 46 of the cylindrical shape. The annular ribs are in sliding contact with the inner peripheral surface of the syringe barrel. The plurality of annular ribs are arranged in the axial direction from a leading end surface (liquid contact surface) 47 of the plunger stopper to a rear end surface 48. The number of annular ribs is not particularly limited as long as it is one or more, but is preferably two or more, more preferably three or more, and preferably six or less, more preferably five or less, and even more preferably four or less.

[0102] The plunger stopper 40 in FIG. 2 has, from the tip side, a first annular rib 43, a second annular rib 44, and a third annular rib 45. The radial compression rate of the first annular rib 43 at the tip is preferably 1% or more, more preferably 2% or more, even more preferably 3% or more, preferably 10% or less, more preferably 9% or less, and even more preferably 8% or less. The compression rate is calculated from the outer diameter D1 of the annular rib in an uncompressed state and the inner diameter R of the syringe barrel using the following formula: Compression rate (%) = 100 × (D1 - R) / D1

[0103] The linear length H1 (the axial length) of the sliding contact portion of the annular rib 43 at the tip is preferably 1% or more, more preferably 3% or more, and even more preferably 6% or more of the linear length Ho of the outer peripheral surface of the cylindrical shape (the axial length of the outer peripheral surface), and is preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less.

[0104] The linear length H2 (axial length) of the sliding contact portion of the second annular rib 44 and the linear length H3 (axial length) of the sliding contact portion of the third annular rib 45 are each preferably 1% or more, more preferably 2% or more, and even more preferably 3% or more, of the linear length Ho (axial length of the outer peripheral surface) of the cylindrical outer peripheral surface, and are preferably 15% or less, more preferably 14% or less, and even more preferably 13% or less.

[0105] The plunger stopper may be called a stopper or a gasket.

[0106] <Rubber stopper> Fig. 3 is an explanatory diagram illustrating an example of a medical stopper to which the present invention is applied. More specifically, it is a rubber stopper for a vial. Fig. 3(a) is a plan view, and Fig. 3(b) is a cross-sectional view taken along line AA in Fig. 3(a).

[0107] The medical plug 50 has a top plate 53 and cylindrical leg portions 55 extending downward from the underside of the top plate 53. The top plate 53 and leg portions 55 are made of a cured rubber composition. When a medical container is stoppered with the medical plug of the present invention, the leg portions 55 fit into the opening of the medical container. In Figure 3(b), the opposing inner surfaces of the cylindrical leg portions 55 are tapered so that the distance between the inner surfaces of the leg portions gradually decreases from the bottom to the top (towards the top surface).

[0108] The top plate 53 has a circular shape in a plan view. The top plate 53 has a puncture portion 53a that can be punctured with the needle of a syringe, and a flange portion 53b that comes into contact with the upper edge surface of the opening of the medical container when the medical container is capped.

[0109] A protrusion 57 is provided on the top surface of flange portion 53b to prevent it from coming into close contact with other rubber stoppers.

[0110] Puncture portion 53a is a region for inserting an injection needle to aspirate the medicinal liquid inside the container on top plate 53. Puncture portion 53a is circular in plan view and is located in the center of top plate 53. Puncture portion 53a is formed in a concave shape on the top surface.

[0111] 3, the entire lower surface of tabletop 53 and the entire surface of leg portion 55 are covered with inactive resin layer 59. Note that inactive resin layer 59 may cover at least a portion of the lower surface of tabletop 53 and the entire surface of leg portion 55. As inactive resin layer 59, a polytetrafluoroethylene film is preferred.

[0112] The top surface of the top plate 53 is not provided with an inactive resin layer, and the cured medical rubber composition is exposed. A vinyl compound is applied to the cured surface of the top plate, and then ultraviolet light is applied. The top surface of the top plate 53 has a reduced coefficient of friction and adhesiveness, which alleviates the problem of rubber stoppers sticking together.

[0113] Figure 4 is an explanatory diagram showing another embodiment of a medical rubber stopper 50 to which the present invention is applied. Figure 4(a) is a plan view, and Figure 4(b) is a cross-sectional view taken along line BB in Figure 4(a). In the medical rubber stopper 50 in Figure 4, parts that have the same configuration as Figure 3 will not be described.

[0114] The medical rubber stopper 50 of this embodiment has bifurcated legs 55 extending from the underside of the top plate 53. In FIG. 4(b), the opposing inner surfaces of the bifurcated legs 55 are tapered so that the distance between the inner surfaces of the legs gradually decreases from bottom to top (toward the top surface). In the embodiment of FIG. 4, the top plate 53 and the legs 55 are made of a cured rubber composition, and the entire underside of the top plate 53 and the entire surface of the legs 55 are coated with an inactive resin layer 59. Note that the inactive resin layer 59 may cover at least a portion of the underside of the top plate 53 and the surfaces of the legs 55.

[0115] The top surface of the top plate 53 is not provided with an inactive resin layer, and the cured medical rubber composition is exposed. A vinyl compound is applied to the cured surface of the top plate, and then ultraviolet light is applied. The top surface of the top plate 53 has a reduced coefficient of friction and adhesiveness, which alleviates the problem of rubber stoppers sticking together.

[0116] A nylon film layer may be provided on the top surface of the top plate 53 of the medical rubber stopper 50 in Figures 3 and 4. By providing a nylon film layer on the top surface of the medical rubber stopper 50, mechanical transportability during pharmaceutical manufacturing can be ensured. In addition, by providing a nylon film layer on the top surface of the medical rubber stopper 50, the surface smoothness of the top surface can be increased, preventing the generation of needle fragments when punctured with an injection needle.

[0117] <Rubber stopper for vacuum blood collection tube> 5 is an explanatory diagram showing an example of a vacuum blood collection tube. A vacuum blood collection tube 90 consists of a bottomed tube 91 and a rubber stopper 93 that seals the opening of the bottomed tube 91. It is designed so that blood can be collected automatically by reducing the pressure inside the blood collection tube.

[0118] FIG. 6 is an explanatory diagram illustrating an example of a medical stopper to which the present invention is applied. It is an explanatory diagram showing an example of a rubber stopper for a vacuum blood collection tube. FIG. 6(a) is a perspective view, and FIG. 6(b) is a cross-sectional view. The rubber stopper for a vacuum blood collection tube has a top plate 94 and a cylindrical leg portion 95 extending downward from the underside of the top plate 94. The top plate 94 and the leg portion 95 are made of an elastic material. The leg portion 95 fits into the opening of the vacuum blood collection tube when the vacuum blood collection tube is stoppered with the rubber stopper. A puncture portion 96, which is an area for inserting an injection needle, is provided in the center of the top plate 94. The puncture portion 96 is formed in a concave shape from the top surface. The underside of the top plate 94 and the entire surface of the leg portion 95 are covered with an inactive resin layer 97. Note that the inactive resin layer 97 may cover at least a portion of the underside of the top plate 94 and the surface of the leg portion 95.

[0119] The top surface of the top plate 94 is not provided with an inactive resin layer, and the cured medical rubber composition is exposed. A vinyl compound is applied to the cured surface of the top plate, and then ultraviolet light is irradiated. The top surface of the top plate 94 has a reduced coefficient of friction and adhesiveness, which alleviates the problem of rubber stoppers sticking together.

[0120] <Nozzle cap> FIG. 7(a) is a cross-sectional view showing an example of a nozzle cap for a medical syringe and the nozzle of a syringe barrel to be fitted with the nozzle cap. FIG. 7(b) is a cross-sectional view showing the nozzle cap fitted over the nozzle. The nozzle cap 81 is integrally formed from a medical rubber composition. The nozzle cap 81 includes a cylindrical portion 86 having an inner diameter D8 slightly smaller than the outer diameter D9 of the nozzle 83, and a needle portion 87 connected to one end (the upper end in the figure) of the cylindrical portion 86. The needle portion 87 is formed in a columnar shape with an outer surface continuous with the cylindrical portion 86. The other end (the lower end in the figure) of the cylindrical portion 86 is provided with an opening 88 for inserting the nozzle 83 into the cylindrical portion 86 and fitting the nozzle cap 81 over the nozzle 83. The inner surface of the nozzle cap 81 and the surface of the lower end of the cylindrical portion 86 are coated with an inactive resin layer 84.

[0121] No inactive resin layer is provided on the outer surface of the nozzle cap 81, exposing the cured medical rubber composition. A vinyl compound is applied to the cured surface of the outer surface of the nozzle cap 81 and then irradiated with ultraviolet light. The outer surface of the nozzle cap 81 has a reduced coefficient of friction and adhesiveness, which alleviates the problem of nozzle caps sticking together. [Example]

[0122] The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the following examples, and all modifications and embodiments that do not deviate from the spirit of the present invention are included within the scope of the present invention.

[0123] [Preparation of medical rubber articles] The materials listed in Table 1 were kneaded using an open roll at 60°C for 20 minutes to prepare a medical rubber composition. The resulting medical rubber composition was crosslinked under molding conditions at 170°C for 15 minutes and then punched into circular slabs (cured medical rubber compositions) with a diameter of 28 mm and a thickness of 2 mm. 1-Octadecene was used as the vinyl compound represented by general formula (1) and dissolved in hexane as a solvent to the concentration shown in Table 1 to prepare a hexane solution containing 1-octadecene. This hexane solution was spray-coated onto the circular slab to the coating amount shown in Table 1 and allowed to dry naturally to prepare a test specimen for ultraviolet irradiation. The test specimen for ultraviolet irradiation was then irradiated with vacuum ultraviolet light (wavelength: 172 nm) under a nitrogen atmosphere to the integrated irradiance shown in Table 1, washed with hexane, and allowed to dry naturally. UV irradiation conditions Irradiation device: Electrodeless excimer 172 nm irradiation device (manufactured by MDCOM Co., Ltd.) Distance between the surface of the cured material and the lamp: 7mm UV intensity: 57.9mW / cm 2 / sec

[0124] [Table 1]

[0125] The details of the ingredients used are as follows: Chlorinated butyl rubber: Exxon (registered trademark) Chlorobutyl 1066 (chlorine content: 1.25 wt%) manufactured by Exxon Mobil Corporation General-purpose butyl rubber: Exxon (registered trademark) Butyl 268 (unsaturation level: 2.30 mol%) manufactured by Exxon Mobil Corporation Triazine derivative: Sankyo Kasei Jisnet DB Sulfur: Insoluble sulfur (Seimi OT) manufactured by Nippon Kanretsu Kogyo Co., Ltd. Zinc oxide: Activated zinc oxide AZO manufactured by Seido Chemical Industry Co., Ltd. Magnesium oxide: Kyowa Chemical Industry Co., Ltd., Magsarat 150s Dithiocarbamate: Noccela (registered trademark) ZTC manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0126] [Evaluation method] (1) Friction coefficient <Measurement of static and dynamic friction coefficients> Figure 8 is an explanatory diagram showing the method for measuring the friction coefficient of the medical rubber article (a circular slab with a thickness of 2 mm and a diameter of 28 mm after UV irradiation) prepared above using a static and dynamic friction coefficient measuring instrument TL201 (manufactured by TAILAB). A measurement sample 63 is fixed to a lower stage 64, and a 10g weight 61 is placed on a dedicated probe equipped with a 10mm diameter SUS ball 62, bringing the surface of the measurement sample 63 into contact with the SUS ball 62. The stage 64 is then moved in the direction of the arrow at a speed of 10mm / sec over a distance of 20mm. The friction force F generated at this time, divided by the load (normal force) N, is taken as the friction coefficient μ (μ=F / N). The coefficient of dynamic friction was calculated by dividing the coefficient by the average normal force N1 over a 20 mm travel distance, and the coefficient of static friction was calculated by dividing the coefficient by the maximum average normal force N2 over a 20 mm travel distance. <Evaluation of static friction coefficient> The static friction coefficient was evaluated according to the following evaluation criteria. ○: The static friction coefficient is less than 1.50. ×: The static friction coefficient is 1.50 or more. <Evaluation of dynamic friction coefficient> The dynamic friction coefficient was evaluated according to the following evaluation criteria. ○: The dynamic friction coefficient is less than 1.30. ×: The dynamic friction coefficient is 1.30 or more.

[0127] (2) Adhesion test <Measurement of tack value> For the medical rubber article (a circular slab with a thickness of 2 mm and a diameter of 28 mm after UV irradiation) prepared as described above, a testing machine EZ-SX (manufactured by Shimadzu Corporation) was used to fix the medical rubber article to a dedicated jig at the bottom, and the upper metal Φ10 mm SUS probe was pressed against the surface of the medical rubber article. After reaching the set pressure (10 N), it was held for 10 seconds and then raised at a speed of 10 mm / sec. The peak value of the adhesion force generated between the probe and the cured rubber composition was defined as the tack value. Measurements were taken on n=5, and the average value of n=3 excluding max and min was taken as the tack value. <Evaluation of adhesiveness> The adhesiveness was evaluated according to the following evaluation criteria. ◯: Tack value is 0.5N or less. ×: The tack value is more than 0.5N.

[0128] (3) Overall evaluation Good: The evaluation results of the friction coefficient and the adhesion were good. ×: Both the evaluation results of the friction coefficient and the evaluation results of the adhesion were ×.

[0129] The measurement and evaluation results of the friction coefficient and adhesion are shown in Table 1. From Table 1, it can be seen that the medical rubber articles obtained by the manufacturing method of the present invention have reduced surface friction coefficients and adhesion. [Industrial Applicability]

[0130] The manufacturing method of the present invention can provide a medical rubber part having a reduced surface friction coefficient and tackiness. The medical rubber article of the present invention can be suitably used as a medical rubber article that requires a low friction coefficient and low tackiness (particularly good sliding properties).

[0131] A preferred embodiment (1) of the present invention comprises the steps of: (a) contacting a cured product of a medical rubber composition containing a halogenated butyl rubber as a base polymer with a vinyl compound represented by the following general formula (1): The method for producing medical rubber articles comprises the step of irradiating the cured product after contact with the vinyl compound with ultraviolet light. R-CH=CH2(1) [In the formula, R represents an alkyl group having 6 or more carbon atoms.]

[0132] A preferred embodiment (2) of the present invention is the method for producing medical rubber articles according to embodiment (1), wherein R in the general formula (1) is an alkyl group having 6 to 20 carbon atoms.

[0133] A preferred embodiment (3) of the present invention is the method for producing a medical rubber article according to embodiment (1) or (2), in which the vinyl compound is brought into contact with the cured product by applying a vinyl compound-containing liquid having a vinyl compound concentration of 2.0 g / L to 25.0 g / L to the cured product.

[0134] A preferred embodiment (4) of the present invention is the method for producing medical rubber articles according to any one of embodiments (1) to (3), wherein the ultraviolet light has a wavelength of 160 nm to 380 nm.

[0135] In a preferred embodiment (5) of the present invention, the cumulative irradiance of ultraviolet light on the cured product after contact with the vinyl compound is 1000 mJ / cm 2 ~50,000mJ / cm 2 This is a method for producing a medical rubber part according to any one of aspects (1) to (4).

[0136] A preferred embodiment (6) of the present invention is the method for producing medical rubber articles according to any one of the embodiments (1) to (5), in which the ultraviolet irradiation is carried out in a nitrogen atmosphere.

[0137] A preferred embodiment (7) of the present invention is the method for producing a medical rubber article according to any one of embodiments (1) to (6), wherein the halogenated butyl rubber is at least one selected from the group consisting of chlorinated butyl rubber, brominated butyl rubber, and a brominated copolymer of isobutylene and p-methylstyrene.

[0138] A preferred embodiment (8) of the present invention is the method for producing a medical rubber article according to any one of the embodiments (1) to (7), in which (a) the base polymer consists solely of halogenated butyl rubber.

[0139] A preferred embodiment (9) of the present invention is the method for producing a medical rubber article according to any one of embodiments (1) to (8), wherein the medical rubber article is a rubber stopper for a vial, a cap for a syringe, a plunger stopper for a syringe, or a rubber stopper for a vacuum blood collection tube.

[0140] A preferred embodiment (10) of the present invention is a method for producing a medical rubber article according to any one of the embodiments (1) to (9), in which at least a portion of the surface of the cured product of the medical rubber composition is coated with an inactive resin layer, and at least a portion of the surface of the cured product that is not coated with the inactive resin layer and is exposed is brought into contact with a vinyl compound and irradiated with ultraviolet light.

[0141] A preferred embodiment (11) of the present invention is the method for producing a medical rubber article according to embodiment (10), wherein the medical rubber article is a syringe plunger stopper having a liquid-contacting surface portion facing a medicinal solution and a sliding surface portion contacting a syringe barrel, the liquid-contacting surface portion being coated with an inactive resin layer, and the sliding surface portion being exposed without being coated with the inactive resin layer.

[0142] A preferred embodiment (12) of the present invention is the method for producing a medical rubber article according to embodiment (10) or (11), in which the inactive resin layer is a layer made of a fluororesin.

[0143] A preferred embodiment (13) of the present invention is the method for producing a medical rubber article according to embodiment (10) or (11), in which the inactive resin layer is a layer made of a non-fluorine-containing resin.

[0144] A preferred embodiment (14) of the present invention is a medical rubber article characterized in that (a) one end of an alkyl chain having 8 or more carbon atoms is chemically bonded to the surface of a cured product of a medical rubber composition containing a halogenated butyl rubber as a base polymer.

[0145] A preferred embodiment (15) of the present invention is the medical rubber part according to embodiment (14), in which the alkyl chain is linear.

Claims

1. (a) contacting a cured product of a medical rubber composition containing a halogenated butyl rubber as a base polymer with a vinyl compound represented by the following general formula (1): A method for producing a medical rubber article, comprising the step of irradiating the cured product after contact with the vinyl compound with ultraviolet light. R-CH=CH ２ (1) [In the formula, R represents an alkyl group having 6 or more carbon atoms.]

2. 2. The method for producing medical rubber articles according to claim 1, wherein R in the general formula (1) is an alkyl group having 6 to 20 carbon atoms.

3. 2. The method for producing medical rubber articles according to claim 1, wherein the vinyl compound is brought into contact with the cured product by applying a vinyl compound-containing liquid having a concentration of the vinyl compound of 2.0 g / L to 25.0 g / L to the cured product.

4. 2. The method for producing medical rubber articles according to claim 1, wherein the ultraviolet light has a wavelength of 160 nm to 380 nm.

5. The cumulative irradiance of ultraviolet light on the cured product after contact with the vinyl compound is 1000 mJ / cm ２ ~50000mJ / cm ２ The method for producing a medical rubber part according to claim 1, wherein

6. The method for producing medical rubber articles according to claim 1, wherein the ultraviolet irradiation is carried out in a nitrogen atmosphere.

7. 2. The method for producing medical rubber articles according to claim 1, wherein the halogenated butyl rubber is at least one selected from the group consisting of chlorinated butyl rubber, brominated butyl rubber, and brominated copolymer of isobutylene and p-methylstyrene.

8. 2. The method of claim 1, wherein (a) the base polymer consists solely of halogenated butyl rubber.

9. 2. The method for producing a medical rubber article according to claim 1, wherein the medical rubber article is a rubber stopper for a vial, a cap for a syringe, a plunger stopper for a syringe, or a rubber stopper for a vacuum blood collection tube.

10. 2. The method for producing a medical rubber article according to claim 1, wherein at least a portion of the surface of the cured product of the medical rubber composition is coated with an inactive resin layer, and at least a portion of the surface of the cured product that is not coated with the inactive resin layer and is exposed is brought into contact with a vinyl compound and irradiated with ultraviolet light.

11. The method for manufacturing a medical rubber article according to claim 10, wherein the medical rubber article is a plunger stopper for a syringe having a liquid contact surface portion facing the medicinal solution and a sliding surface portion contacting the syringe barrel, the liquid contact surface portion being coated with an inactive resin layer, and the sliding surface portion being exposed and not coated with the inactive resin layer.

12. The method for producing medical rubber articles according to claim 10, wherein the inactive resin layer is a layer made of a fluororesin.

13. The method for producing medical rubber articles according to claim 10, wherein the inactive resin layer is a layer made of a non-fluorine-containing resin.

Images